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Shan Z, Song X, Yang X, Xue Y, Wu Y, Wang X, Liu J, Liu Q. Calreticulin (CALR) promotes ionophore-induced microneme secretion in Toxoplasma gondii. Parasitol Res 2024; 123:139. [PMID: 38381180 DOI: 10.1007/s00436-024-08162-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2023] [Accepted: 02/11/2024] [Indexed: 02/22/2024]
Abstract
The flow of calcium ions (Ca2+) is involved in numerous vital activities of Toxoplasma gondii. Calreticulin is a type of Ca2+-binding protein in the endoplasmic reticulum (ER) that is involved in Ca2+ signaling pathway regulation, Ca2+ storage, and protein folding. In this work, the calreticulin (CALR), a protein predicted to possess a conserved domain of calreticulin in T. gondii, was characterized. The CALR localized in the ER. Using reverse genetics, we discovered that CALR is not necessary for the lytic cycle, including invasion and replication. However, depletion of CALR affected microneme secretion triggered by A23187, which is a Ca2+ ionophore used to increase cytoplasmic Ca2+ concentration. Furthermore, we discovered that CALR influences Ca2+ release. Transcriptomic comparison between Δcalr and Δku80 parasites showed that 226 genes in the Δcalr parasites were significantly downregulated (p < 0.05). The cellular biological functions of the downregulated genes were mainly involved in calmodulin-dependent protein kinase pathways. Furthermore, in the absence of CALR, tachyzoites were still able to cause acute infection in mice. These results imply that by influencing ER Ca2+ release content, CALR may further impair the ionophore-induced secretion of the parasite. However, this protein is not required for the completion of the parasite's lytic cycle or for the acute virulence of the parasite.
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Affiliation(s)
- Zhili Shan
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Xingju Song
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
- College of Animal Science and Technology, Guangxi University, Nanning, 530004, China
| | - Xu Yang
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Yangfei Xue
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Yayun Wu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
- College of Veterinary Medicine, Henan Agricultural University, Zhengzhou, 450046, China
| | - Xianmei Wang
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Jing Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China
| | - Qun Liu
- National Animal Protozoa Laboratory, College of Veterinary Medicine, China Agricultural University, Beijing, 100193, China.
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2
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Kim H, Hong SH, Jeong HE, Han S, Ahn J, Kim JA, Yang JH, Oh HJ, Chung S, Lee SE. Microfluidic model for in vitro acute Toxoplasma gondii infection and transendothelial migration. Sci Rep 2022; 12:11449. [PMID: 35794197 PMCID: PMC9259589 DOI: 10.1038/s41598-022-15305-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 06/22/2022] [Indexed: 11/10/2022] Open
Abstract
The protozoan parasite Toxoplasma gondii (T. gondii) causes one of the most common human zoonotic diseases and infects approximately one-third of the global population. T. gondii infects nearly every cell type and causes severe symptoms in susceptible populations. In previous laboratory animal studies, T. gondii movement and transmission were not analyzed in real time. In a three-dimensional (3D) microfluidic assay, we successfully supported the complex lytic cycle of T. gondii in situ by generating a stable microvasculature. The physiology of the T. gondii-infected microvasculature was monitored in order to investigate the growth, paracellular and transcellular migration, and transmission of T. gondii, as well as the efficacy of T. gondii drugs.
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Affiliation(s)
- Hyunho Kim
- School of Mechanical Engineering, Korea University, Seoul, Republic of Korea.,Center for Systems Biology, Massachusetts General Hospital Research Institute, Boston, MA, USA
| | - Sung-Hee Hong
- Division of Vectors and Parasitic Diseases, Korea Diseases Control and Prevention Agency, Cheongju, Republic of Korea
| | - Hyo Eun Jeong
- School of Mechanical Engineering, Korea University, Seoul, Republic of Korea
| | | | - Jinchul Ahn
- School of Mechanical Engineering, Korea University, Seoul, Republic of Korea
| | - Jin-A Kim
- School of Mechanical Engineering, Korea University, Seoul, Republic of Korea
| | | | - Hyun Jeong Oh
- School of Mechanical Engineering, Korea University, Seoul, Republic of Korea.
| | - Seok Chung
- School of Mechanical Engineering, Korea University, Seoul, Republic of Korea. .,KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.
| | - Sang-Eun Lee
- Division of Vectors and Parasitic Diseases, Korea Diseases Control and Prevention Agency, Cheongju, Republic of Korea.
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3
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Harun MSR, Marsh V, Elsaied NA, Webb KF, Elsheikha HM. Effects of Toxoplasma gondii infection on the function and integrity of human cerebrovascular endothelial cells and the influence of verapamil treatment in vitro. Brain Res 2020; 1746:147002. [PMID: 32592740 DOI: 10.1016/j.brainres.2020.147002] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2018] [Revised: 06/07/2020] [Accepted: 06/20/2020] [Indexed: 12/16/2022]
Abstract
Toxoplasma gondii can cause parasitic encephalitis, a life-threatening infection that predominately occurs in immunocompromised individuals. T. gondii has the ability to invade the brain, but the mechanisms by which this parasite crosses the blood-brain-barrier (BBB) remain incompletely understood. The present study reports the changes associated with infection and replication of T. gondii within human brain microvascular endothelial cells (BMECs) in vitro. Our results indicated that exposure to T. gondii had an adverse impact on the function and integrity of the BMECs - through induction of cell cycle arrest, disruption of the BMEC barrier integrity, reduction of cellular viability and vitality, depolarization of the mitochondrial membrane potential, increase of the DNA fragmentation, and alteration of the expression of immune response and tight junction genes. The calcium channel/P-glycoprotein transporter inhibitor verapamil was effective in inhibiting T. gondii crossing the BMECs in a dose-dependent manner. The present study showed that T. gondii can compromise several functions of BMECs and demonstrated the ability of verapamil to inhibit T. gondii crossing of the BMECs in vitro.
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Affiliation(s)
- M S R Harun
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK; Infectomics Cluster, Advanced Medical & Dental Institute, Universiti Sains Malaysia, Bertam, 13200 Kepala Batas, Pulau Pinang, Malaysia
| | - Victoria Marsh
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK
| | - Nashwa A Elsaied
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK
| | - Kevin F Webb
- Department of Electrical & Electronic Engineering, University of Nottingham, Nottingham NG7 2RD, UK
| | - Hany M Elsheikha
- Faculty of Medicine and Health Sciences, School of Veterinary Medicine and Science, University of Nottingham, Sutton Bonington Campus, Leicestershire LE12 5RD, UK.
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Nayeri T, Sarvi S, Moosazadeh M, Hosseininejad Z, Amouei A, Daryani A. Toxoplasma gondii infection and risk of attention-deficit hyperactivity disorder: a systematic review and meta-analysis. Pathog Glob Health 2020; 114:117-126. [PMID: 32186992 DOI: 10.1080/20477724.2020.1738153] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Toxoplasma gondii (T. gondii), as an opportunistic neurotropic parasite of the Apicomplexa family, was firstly described in 1908. As attention-deficit hyperactivity disorder (ADHD) is one of the most common neuropsychiatric disorders in children and adolescents and often persists into adulthood, the purpose of this systematic review and meta-analysis was to investigate the relationship between T. gondii infection and ADHD.The data were systematically collected from seven electronic databases up to May 1st 2019 with no language restriction. This study was registered at the International Prospective Register of Systematic Reviews (PROSPERO; code: CRD42020149353). Odds ratios (ORs) and 95% confidence intervals (CI) were estimated using a random effects model. Seven studies involving five cross-sectional and two case-control studies were included in this meta-analysis.Results indicated that there was a statistically non-significant association between exposure to T. gondii infection and increased risk of ADHD based on the detection of immunoglobulin G (IgG) antibody (2.02 [95% CI: 0.97-4.20]; I2=58.7%). However, obtained results of Egger's tests for anti-T. gondii IgG antibody showed publication bias (P=0.014).Sensitivity analysis revealed stable results for the association between anti-T. gondii IgG antibody with ADHD.Given the small number of studies in this field and the obtained results, it cannot be conclusively stated that T. gondii is a risk factor for ADHD.It is important to have reliable information about the relationship between T. gondii and ADHD around the world; as it may lead to better insight to elucidate the possible association of toxoplasmosis and the pathogenesis of ADHD.
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Affiliation(s)
- Tooran Nayeri
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Shahabeddin Sarvi
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Mahmood Moosazadeh
- Health Sciences Research Center, Addiction Institute, Mazandaran University of Medical Sciences, Sari, Iran
| | - Zahra Hosseininejad
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran.,Student Research Committee, Mazandaran University of Medical Sciences, Sari, Iran
| | - Afsaneh Amouei
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ahmad Daryani
- Department of Parasitology, School of Medicine, Mazandaran University of Medical Sciences, Sari, Iran.,Toxoplasmosis Research Center, Mazandaran University of Medical Sciences, Sari, Iran
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Resistance towards monensin is proposed to be acquired in a Toxoplasma gondii model by reduced invasion and egress activities, in addition to increased intracellular replication. Parasitology 2017; 145:313-325. [PMID: 28870270 DOI: 10.1017/s0031182017001512] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Monensin (Mon) is an anticoccidial polyether ionophore widely used to control coccidiosis. The extensive use of polyether ionophores on poultry farms resulted in widespread resistance, but the underlying resistance mechanisms are unknown in detail. For analysing the mode of action by which resistance against polyether ionophores is obtained, we induced in vitro Mon resistance in Toxoplasma gondii-RH strain (MonR-RH) and compared it with the sensitive parental strain (Sen-RH). The proteome assessment of MonR-RH and Sen-RH strains was obtained after isotopic labelling using stable isotope labelling by amino acid in cell culture. Relative proteomic quantification between resistant and sensitive strains was performed using liquid chromatography-mass spectrometry/mass spectrometry. Overall, 1024 proteins were quantified and 52 proteins of them were regulated. The bioinformatic analysis revealed regulation of cytoskeletal and transmembrane proteins being involved in transport mechanisms, metal ion-binding and invasion. During invasion, actin and microneme protein 8 (MIC8) are seem to be important for conoid extrusion and forming moving junction with host cells, respectively. Actin was significantly upregulated, while MIC8 was downregulated, which indicate an invasion reduction in the resistant strain. Resistance against Mon is not a simple process but it involves reduced invasion and egress activity of T. gondii tachyzoites while intracellular replication is enhanced.
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SARAEI M, GHADERI Y, MOSAVI T, SHAHNAZI M, NASSIRI-ASL M, JAHANIHASHEMI H. The Effect of Fluphenazine and Thioridazine on Toxoplasma gondii In Vivo. IRANIAN JOURNAL OF PARASITOLOGY 2016; 11:226-231. [PMID: 28096857 PMCID: PMC5236100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
BACKGROUND Toxoplasma gondii is the most common parasite causing latent cerebral infections in human. It has been shown that some anti-psychotic drugs are able to inhibit the proliferation of the parasite in in vitro study. There is very limited data regarding the inhibitory effect of anti-psychotics on Toxoplasma in in vivo. In this study, we evaluated anti-Toxoplasma activity of fluphenazine and thioridazine drugs on T. gondii in mice. METHODS Mice were divided into six groups: Control, sesame as vehicle, thioridazine 10 mg/kg, thioridazine 20 mg/kg, fluphenazine 0.06 mg/kg and fluphenazine 0.6 mg/kg. They were inoculated intraperitoneally with brain suspension containing tissue cysts of T. gondii Tehran strain. Two months after inoculation, the number of cysts in crushed smears of mice brain were counted microscopically and considered as an indicator of anti-Toxoplasma activity. This work has conducted in Qazvin, central Iran, 2014. RESULTS Our study showed that fluphenazine and thioridazine could not significantly inhibit the brain cystogenesis of T. gondii in mice. However, the number of brain cysts was less at higher dose compared to lower doses for both drugs. CONCLUSION Further studies need to clear the mechanism of different structure of anti-psychotic drugs on activity of Toxoplasma.
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Affiliation(s)
- Mehrzad SARAEI
- Dept. of Medical Parasitology and Mycology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran,Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Yosef GHADERI
- Dept. of Medical Parasitology and Mycology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Tahereh MOSAVI
- Dept. of Medical Parasitology and Mycology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Mojtaba SHAHNAZI
- Dept. of Medical Parasitology and Mycology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran,Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Marjan NASSIRI-ASL
- Cellular and Molecular Research Center, Qazvin University of Medical Sciences, Qazvin, Iran,Dept. of Pharmacology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran,Correspondence
| | - Hassan JAHANIHASHEMI
- Dept. of Community Medicine, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
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8
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Hong S, Lee HA, Lee YS, Chung YH, Kim O. Anti-toxoplasmosis effect of Dictamnus dasycarpus extract against Toxoplasma Gondii. J Biomed Res 2014. [DOI: 10.12729/jbr.2014.15.1.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
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9
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Caldas LA, Seabra SH, Attias M, de Souza W. The effect of kinase, actin, myosin and dynamin inhibitors on host cell egress by Toxoplasma gondii. Parasitol Int 2013; 62:475-82. [DOI: 10.1016/j.parint.2013.04.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2012] [Revised: 03/26/2013] [Accepted: 04/18/2013] [Indexed: 12/21/2022]
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10
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Interplay of host-pathogen microvesicles and their role in infectious disease. Biochem Soc Trans 2013; 41:258-62. [PMID: 23356293 DOI: 10.1042/bst20120257] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The release of extracellular vesicles, whether MVs (microvesicles) or exosomes, from host cells or intracellular pathogens is likely to play a significant role in the infection process. Host MVs may fuse with pathogen surfaces to deliver host complement regulatory proteins. They may also deliver cytokines that enhance invasion. Decoy functions are also possible. Whereas host MVs may direct pathogens away from their target cells, pathogen MVs may in turn redirect complement membrane-attack complexes away from their target pathogen. An understanding of the mechanisms of this interplay, bringing about both immune evasion and enhanced invasion, will help to direct future research with a view to rendering pathogens more susceptible to immune attack or in improving drug efficacy. It should also be possible to use MVs or exosomes isolated directly from the pathogens, or from the cells infected with pathogens, to provide alternative vaccination strategies.
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Carter CJ. Toxoplasmosis and Polygenic Disease Susceptibility Genes: Extensive Toxoplasma gondii Host/Pathogen Interactome Enrichment in Nine Psychiatric or Neurological Disorders. J Pathog 2013; 2013:965046. [PMID: 23533776 PMCID: PMC3603208 DOI: 10.1155/2013/965046] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2012] [Revised: 08/18/2012] [Accepted: 09/10/2012] [Indexed: 01/04/2023] Open
Abstract
Toxoplasma gondii is not only implicated in schizophrenia and related disorders, but also in Alzheimer's or Parkinson's disease, cancer, cardiac myopathies, and autoimmune disorders. During its life cycle, the pathogen interacts with ~3000 host genes or proteins. Susceptibility genes for multiple sclerosis, Alzheimer's disease, schizophrenia, bipolar disorder, depression, childhood obesity, Parkinson's disease, attention deficit hyperactivity disorder (P from 8.01E - 05 (ADHD) to 1.22E - 71) (multiple sclerosis), and autism (P = 0.013), but not anorexia or chronic fatigue are highly enriched in the human arm of this interactome and 18 (ADHD) to 33% (MS) of the susceptibility genes relate to it. The signalling pathways involved in the susceptibility gene/interactome overlaps are relatively specific and relevant to each disease suggesting a means whereby susceptibility genes could orient the attentions of a single pathogen towards disruption of the specific pathways that together contribute (positively or negatively) to the endophenotypes of different diseases. Conditional protein knockdown, orchestrated by T. gondii proteins or antibodies binding to those of the host (pathogen derived autoimmunity) and metabolite exchange, may contribute to this disruption. Susceptibility genes may thus be related to the causes and influencers of disease, rather than (and as well as) to the disease itself.
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Affiliation(s)
- C. J. Carter
- Polygenic Pathways, Flat 2, 40 Baldslow Road, Hastings, East Sussex TN34 2EY, UK
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12
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Prole DL, Marrion NV. Identification of putative potassium channel homologues in pathogenic protozoa. PLoS One 2012; 7:e32264. [PMID: 22363819 PMCID: PMC3283738 DOI: 10.1371/journal.pone.0032264] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Accepted: 01/24/2012] [Indexed: 12/21/2022] Open
Abstract
K+ channels play a vital homeostatic role in cells and abnormal activity of these channels can dramatically alter cell function and survival, suggesting that they might be attractive drug targets in pathogenic organisms. Pathogenic protozoa lead to diseases such as malaria, leishmaniasis, trypanosomiasis and dysentery that are responsible for millions of deaths each year worldwide. The genomes of many protozoan parasites have recently been sequenced, allowing rational design of targeted therapies. We analyzed the genomes of pathogenic protozoa and show the existence within them of genes encoding putative homologues of K+ channels. These protozoan K+ channel homologues represent novel targets for anti-parasitic drugs. Differences in the sequences and diversity of human and parasite proteins may allow pathogen-specific targeting of these K+ channel homologues.
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Affiliation(s)
- David L Prole
- Department of Pharmacology, University of Cambridge, Cambridge, United Kingdom.
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Jin C, Jung SY, Kim SY, Song HO, Park H. Simple and efficient model systems of screening anti-Toxoplasmadrugsin vitro. Expert Opin Drug Discov 2012; 7:195-205. [DOI: 10.1517/17460441.2012.660479] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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14
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In vitro effects of aqueous extracts of Astragalus membranaceus and Scutellaria baicalensis GEORGI on Toxoplasma gondii. Parasitol Res 2011; 110:2221-7. [DOI: 10.1007/s00436-011-2752-2] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/13/2011] [Accepted: 11/30/2011] [Indexed: 12/22/2022]
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Reimão JQ, Tempone AG. Investigation into in vitro anti-leishmanial combinations of calcium channel blockers and current anti-leishmanial drugs. Mem Inst Oswaldo Cruz 2011; 106:1032-8. [DOI: 10.1590/s0074-02762011000800022] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2011] [Accepted: 10/25/2011] [Indexed: 11/21/2022] Open
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In vitro and experimental therapeutic studies of the calcium channel blocker bepridil: Detection of viable Leishmania (L.) chagasi by real-time PCR. Exp Parasitol 2011; 128:111-5. [DOI: 10.1016/j.exppara.2011.02.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2010] [Revised: 12/13/2010] [Accepted: 02/21/2011] [Indexed: 11/22/2022]
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Prandota J. The importance of toxoplasma gondii infection in diseases presenting with headaches. Headaches and aseptic meningitis may be manifestations of the Jarisch-Herxheimer reaction. Int J Neurosci 2010; 119:2144-82. [PMID: 19916846 DOI: 10.3109/00207450903149217] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Worldwide, approximately 2 billion people are chronically infected with T. gondii with largely unknown consequences. This review presents clinical symptoms, differential diagnosis, triggering factors, treatment, and pathomechanisms responsible for idiopathic intracranial hypertension, pseudotumor cerebri, and aseptic meningitis. Literature cited in this work illustrates that immune state and other biologic mediator imbalances due to various endogenous and exogenous triggering factors may markedly affect latent central nervous system T. gondii infection/inflammation intensity, and cause reactivation of cerebral toxoplasmosis (CT). Irregularities in pro- and anti-inflammatory processes may markedly disturb the host and/or T. gondii defense mechanisms important for immune control of the parasite thereby manifesting as a wide range of neurologic symptoms and signs observed in some patients with migraine, epilepsy, celiac disease, Henoch-Schönlein purpura, and other brain disorders. This is consistent with reactivation of CT in mice after treatment with dexamethasone associated with depression of type T(H)1 immune response, and development of CT after administration of etanercept or other bioproducts. It seems that various types of headaches, epilepsy, aseptic meningitis, systemic adverse reactions to drugs or other substances represent the Jarisch-Herxheimer reaction due to apoptosis of T. gondii tachyzoites. Also development of some brain tumors, such as ependymoma and glioma may be associated with a chronic course of CT. Thus, all these patients should be tested for T. gondii infection.
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Affiliation(s)
- Joseph Prandota
- Department of Social Pediatrics, Faculty of Public Health, University Medical School, Wroclaw, Poland.
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Caldas LA, de Souza W, Attias M. Microscopic analysis of calcium ionophore activated egress of Toxoplasma gondii from the host cell. Vet Parasitol 2009; 167:8-18. [PMID: 19875235 DOI: 10.1016/j.vetpar.2009.09.051] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2009] [Revised: 09/09/2009] [Accepted: 09/28/2009] [Indexed: 11/17/2022]
Abstract
Toxoplasma gondii invades and destroys nucleated cells of warm blooded hosts in a process which involves several steps: recognition, adhesion, penetration, multiplication inside a parasitophorous vacuole (PV) and egress. The last one is the least understood. Parasite egress from LLC-MK2 cells infected with the RH strain of T. gondii was artificially triggered with 4BrA23187 calcium ionophore. The combination of videomicroscopy, field emission scanning electron microscopy (FESEM), and transmission electron microscopy (TEM) showed that egress does not result from host cell rupture due to overloading with tachyzoites. Videomicroscopy showed that upon calcium ionophore administration parasite rosettes disassemble, the contour of the parasitophorous vacuole disappears and each tachyzoite takes a separate route to the extracellular medium. FESEM and TEM showed the fragmentation of the intravacuolar network, the fragmentation of parasitophorous vacuole membrane and individual tachyzoites with extruded conoids migrating through the cytosol, tightly surrounded by remnants of parasitophorous vacuole membrane or free in the cytosol. Both videomicroscopy and FESEM showed that a single parasite can cross the host cell membrane without disrupting it, while a large number of parasites, egressing simultaneously, rupture the membrane and the cell as a whole. These data suggest that invasion and egress share less similarities than previously believed.
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Affiliation(s)
- Lucio Ayres Caldas
- Laboratório de Ultraestrutura Celular Hertha Meyer, Instituto de Biofísica Carlos Chagas Filho, Universidade Federal do Rio de Janeiro, Brazil
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Del Carmen MG, Mondragón M, González S, Mondragón R. Induction and regulation of conoid extrusion inToxoplasma gondii. Cell Microbiol 2009; 11:967-82. [DOI: 10.1111/j.1462-5822.2009.01304.x] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
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Abstract
Apicomplexan parasites rely on calcium-mediated signaling for a variety of vital functions including protein secretion, motility, cell invasion, and differentiation. These functions are controlled by a variety of specialized systems for uptake and release of calcium, which acts as a second messenger, and on the functions of calcium-dependent proteins. Defining these systems in parasites has been complicated by their evolutionary distance from model organisms and practical concerns in working with small, and somewhat fastidious cells. Comparative genomic analyses of Toxoplasma gondii, Plasmodium spp. and Cryptosporidium spp. reveal several interesting adaptations for calcium-related processes in parasites. Apicomplexans contain several P-type Ca2+ ATPases including an ER-type reuptake mechanism (SERCA), which is the proposed target of artemisinin. All three organisms also contain several genes related to Golgi PMR-like calcium transporters, and a Ca2+/H+ exchanger, while plasma membrane-type (PMCA) Ca2+ ATPases and voltage-dependent calcium channels are exclusively found in T. gondii. Pharmacological evidence supports the presence of IP3 and ryanodine channels for calcium-mediated release. Collectively these systems regulate calcium homeostasis and release calcium to act as a signal. Downstream responses are controlled by a family of EF-hand containing calcium binding proteins including calmodulin, and an array of centrin and caltractin-like genes. Most surprising, apicomplexans contain a diversity of calcium-dependent protein kinases (CDPK), which are commonly found in plants. Toxoplasma contains more than 20 CDPK or CDPK-like proteases, while Plasmodium and Cryptosporidium have fewer than half this number. Several of these CDPKs have been shown to play vital roles in protein secretion, invasion, and differentiation, indicating that disruption of calcium-regulated pathways may provide a novel means for selective inhibition of parasites.
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Wu X, Zhang Q, Tan K, Xie R, Fan J, Shu H, Wang S. Characterization of a new gene WX2 in Toxoplasma gondii. Acta Biochim Biophys Sin (Shanghai) 2007; 39:475-83. [PMID: 17627323 DOI: 10.1111/j.1745-7270.2007.00302.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
Abstract
Using hybridization techniques, we prepared the monoclonal antibody (Mab) 7C3-C3 against Toxoplasma gondii. The protection tests showed that the protein (Mab7C3-C3) inhibited the invasion and proliferation of T. gondii RH strain in HeLa cells. The passive transfer test indicated that the antibody significantly prolonged the survival time of the challenged mice. It was also shown that the antibody could be used for the detection of the circulating antigen of T. gondii. After immunoscreening the T. gondii tachyzoite cDNA library with Mab7C3-C3, a new gene wx2 of T. gondii was obtained. Immunofluorescence analysis showed that the WX2 protein was located on the membrane of the parasite. Nucleotide sequence comparison showed 28% identity to the calcium channel alpha-1E unit and shared with the surface antigen related sequence in some conservative residues. However, no match was found in protein databases. Therefore, it was an unknown gene in T. gondii encoding a functional protein on the membrane of T. gondii. Because it has been shown to have a partial protective effect against T. gondii infection and is released as a circulating antigen, it could be a candidate molecule for vaccine or a novel target for new drugs.
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Affiliation(s)
- Xiang Wu
- Department of Parasitology, Xiangya Medical School, Central South University, Changsha 410078, China
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Mital J, Schwarz J, Taatjes DJ, Ward GE. Laser scanning cytometer-based assays for measuring host cell attachment and invasion by the human pathogen Toxoplasma gondii. Cytometry A 2006; 69:13-9. [PMID: 16342112 PMCID: PMC1428790 DOI: 10.1002/cyto.a.20202] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND Toxoplasma gondii is among the most common protozoan parasites of humans. Both attachment to and invasion of host cells by T. gondii are necessary for infection, yet little is known about the molecular mechanisms underlying these processes. T. gondii's etiological importance and its role as a model organism for studying invasion in related parasites necessitate a means to quantitatively assay host cell attachment and invasion. METHODS We present here Laser Scanning Cytometer (LSC)-based assays of T. gondii invasion and attachment. The invasion assay involves automated counting of invaded and non-invaded parasites, differentially labeled with distinct fluorochromes. The attachment assay compares the relative binding of differentially labeled parasites. The assays were evaluated using treatments known to decrease invasion or attachment. RESULTS The LSC-based assays are robust and reproducible, remove operator bias, and significantly increase the sample size that can be feasibly counted compared to other currently available microscope-based methods. In the first application of the new assays, we have shown that parasites attach to fixed and unfixed host cells using different mechanisms. CONCLUSIONS The LSC-based assays represent useful new methods for quantitatively measuring attachment and invasion by T. gondii, and can be readily adapted to study similar processes in other host-pathogen systems.
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Affiliation(s)
| | | | - Douglas J. Taatjes
- Department of Pathology and
- Microscopy Imaging Center University of Vermont, Burlington, VT 05405
| | - Gary E. Ward
- Department of Microbiology and Molecular Genetics
- *Corresponding author. Mailing address: University of Vermont, Department of Microbiology and Molecular Genetics, 316 Stafford Hall, 95 Carrigan Drive, Burlington, VT 05405. Phone: (802) 656-4868. Fax: (802) 656-8749.
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